The hieroglyphs for Amenemhat can be found naming the Black Pyramid and White Pyramid and refers to Townsend Avalanche when under the influence of an electric field.

The Avalanche effect is the magnification of negative charge occuring between two electrodes. The original ionisation event liberates one electron, and each subsequent collision liberates a further electron, so two electrons emerge from each collision: the ionising electron and the liberated electron.

Townsend Avalanche - Negative Charge Magnification

At low voltages, the only current is that due to the generation of charge carriers in the gas by cosmic rays or other sources of ionizing radiation. As the applied voltage is increased, the free electrons carrying the current gain enough energy to cause further ionization, causing an electron avalanche. In this regime, the current increases or is magnified by nine orders of magnitude, for very little further increase in voltage. The voltage-current characteristics begins tapering off near the breakdown voltage and the glow becomes visible.

The discharge requires a source of free electrons and a significant electric field; without both, the phenomenon does not occur.